Due to the quick growth of smart phone penetration, data traffic in mobile networks is experiencing an explosive growth. Among all mobile data traffic, video streaming is one important part. Along this trend, several streaming delivery methods have being deployed. Among all methods, Content Delivery Networks, CDN and Peer-to-peer, P2P are two important approaches to deliver streaming content over networks. Recently, some P2P based live streaming systems have being quite successful in context of fixed access networks. P2P streaming system is quite scalable by making use of uplink contribution from large amount of peers. Due to the advantage of P2P systems, several CDN players start introducing P2P into their CDN system.
On the other hand, existing P2P streaming systems are facing some problems in the context of mobile networks. For example, it is possible that one or more mobile peers involved in a P2P streaming application are located in the same area, such same cell/Base Station, BS or same Radio Access Network, RAN. While, according to current mobile network principles, a packet gateway node such as a P-GW/GGSN is the only IP anchor point for all user equipment, UEs served by it, and all IP traffic from/to UEs should be routed through the P-GW/GGSN. Therefore, the problem like triangle routing of mobile IPv4 would happen. The problem is more serious in case a large number of mobile peers are involved in streaming applications.
The problems are illustrated by three scenarios in FIGS. 1 to 3.
Summarizing these scenarios, in FIG. 1 a mobile peer A located in a radio access network (111) involved in a P2P application may fetch a chunk of streaming content 132 from a server 131 in a content distribution network, CDN 130 and another chunk of data of the same streaming from another mobile peer B located in the same cell. Meanwhile, peer A may also fetch a different chunk of data of the same streaming from peer C located at a different base station but the same packet gateway node, S-GW (121) as in FIG. 2. Meanwhile, it may also fetch some chunks from peer D located at a different base station, a different S-GW (123) but the same packet gateway node, P-GW (122). In existing mobile networks, typically all IP traffic from/to a UE should be forwarded to P-GW (122), where IP traffic is routed to different destinations.
So, obviously, certain backhaul transport resources and core network element resources would be wasted in case a lot of IP traffic is exchanged between mobile peers local in same area. One problem is how to localize related P2P traffic. Another problem is how to enforce such traffic localization (P2P traffic turning). Another problem is how to recognize the right traffic for localization and which node to make decision for traffic localization. Yet another problem is to select factors that should be taken into account when deciding that certain traffic between certain peers should be localized or not. For example, due to some special requirements related to national security (as lawful interception) or charging considerations from operators, it is not permitted to enforce such traffic localization for certain UEs and certain traffic. While for other UEs and traffic it is possible. Another example, it is possible that certain UEs located in certain areas are not permitted for traffic localization. In addition, it is possible that traffic localization between certain peers is only expected due to some dynamic reasons, for example, the load in core network or backhaul transport network is about to be overloaded.
P2P traffic localization has been discussed both in the academic world and within industry and can basically be categorized into two types:
Type 1: Peer-driven biased neighbour selection for traffic localization.
The general idea of this approach is that, a specific peer performs optimized neighbour selection locally by various metrics, such as: latency based topology maps, Autonomous System, AS mapping and other related metrics locality-aware neighbour selection.
Type 2: ISP-driven biased neighbour selection for traffic localization.
The general thinking of this approach is that the ISP provides an underlay network info by some network elements to P2P application system for optimized peer selection. For example one or more trackers could be introduced by an operator to facilitate P2P system for more reasonable peer selection. Two important methods in this direction are: P4P framework and ALTO. Both of them are under development in different IETF working groups.
However, these prior art focus on ISP and fixed network level traffic localization. None of them has paid attention to traffic localization for mobile networks.